Twelve Russian citizens suspected by Ankara of having links to the Islamic State (IS) extremist group have been detained in Istanbul.

Turkish media reports said police from Istanbul's counterterrorism unit detained the suspects in raids on October 20 and 21.

According to reports, the 12 are from Russia's North Caucasus.

One of the suspects, identified as Mohammed al-Haj, is reportedly from Chechnya, while the others were reported to be from Daghestan.

Mohammed al-Haj along with two other suspects -- identified as Aslan T. and Makhmud S. -- are suspected by Ankara of having been senior leaders of IS in Daghestan and Chechnya.

The other nine men detained were allegedly planning to travel from Turkey to Syria to join IS militants fighting there.

Last month, First Deputy Director of Russia's Federal Security Service Sergei Smirnov said that some 2,400 Russian citizens are fighting alongside IS militants and other extremist Muslim groups in Syria and Iraq.